Apparatus for demonstrating the adhesion of flat surfaces



Feb. 19, 1935. c. E. JOHANSSON APPARATUS FOR DEMONSTRATING THE ADHESION OF FLAT SURFACES I Filed April 15, 1953 @N ON Patented Feb. 19, 1935 1 UNITED STATES PATENT OFFICE APPARATUS FOR DEMONSTRATING THE ADHESION OF FLAT SURFACES Carl Edvard Johansson, Detroit, Mich.

Application April 13, 1933, Serial No. 665,901

4 Claims. (01. 35-12) This invention relates to improvements in ap- Fig. 6 is an enlarged view of a wire attaching paratus for demonstrating the adhesion of fiat ring. surfaces, such as the accurately finished surfaces The apparatus may be mounted on a suitable of Johansson gauges. base plate 11, having upright standards or posts Such gauges, in the form of flat plates, are 12 thereon, carrying a horizontal plate 13 5 made in various thicknesses, the dimensions bethrough which is inserted a hook 14, said hook ing accurate to a very small fraction of a thoubeing adjusted vertically by a nut 15. From sandth of an inch, and in some cases to within said hook is suspended a scale 16 by means of an a millionth of an inch. The surfaces of such eye bolt 17. Said scale may be of any suitable plates approach so closely to true plane surfaces standard manufacture, having the usual hand 10 that when two of said plates, having for example which indicates the pull applied in pounds or an area of one half of one square inch each, are other standards of weight. The pull is applied wrung together by sliding one over the other by means of a hook 18 at the bottom. with a turning motion and pressing them to- The blocks 19 and 20, the adhesion of which it gether at the same time, said plates cannot be is desired to demonstrate, are made preferably of 15 pulled apart by hand, so firmly do they adhere. steel, with adjoining faces 21 smooth and plane, If the air between the two plates were entirely i. e. finished similarly to the Johansson gauge squeezed out, the force necessary to pull them blocks above referred to. These pieces of steel, apart, assuming they were held together by air as shown, are in the form of comparatively thick pressure only, would be about seven pounds, blocks so that they may be drilled and tapped for 20 whereas in practice, the force required is several hooks 0r y b01175 through which t e ce is times this amount and may exceed one hundred applied tending to pull them apart. It will be pounds per half square inch. This phenomenon understood, however, that they may be made in is so diflicult of explanation that it has been the the form of plates, and attached to the assubject of considerable speculation and it resociated parts in various difierent ways.

quires demonstration to overcome the incredulity Furthermore, more than two blocks or plates of the layman. may be wrung together to form of series of such The apparatus selected as the preferred emplates or gauges, the pull being applied to the .bodiment of the present invention is designed to top and bottom plate of the series.

demonstrate, in striking fashion, the adhesion of The upper plate or block may be suspended by 30 Y such plates, or of blocks of metal having engaging means of an eyelet or eye bolt 22 screwed therein, surfaces of comparable accuracy. Such demonand the lower plate or block may have a similar stration apparatus may be used as an advertising eyelet or eye bolt 23 screwed therein, from which display in windows, or at expositions, for exa flexible tension member such as a wire 24 may ample, or for educational or other purposes. be attached. Said wire runs over a pulley 25 35 The objection of the invention is to provide mounted in a frame 26 on the base. The other apparatus for indicating plainly, by a scale r th end of said wire is fastened to a ring 2'7 which like, the pull which such blocks may withstand. Su d a p bolt 8 adjustably secured to Cpntributory objects are to provide apparatus the SlOlitGd. crank 29. Said crank 18 mounted on 40 by which the force tending to separate the blocks the Shaft 30 of a motor driven Speed reducing 40 may be applied intermittently and automatically Vice 311 Which may be of any Suitable type, 170 by a motor driven device whereby the demonrotate 531d shaft stration may be continued for long periods of In operatloll' when P motor 15 started the time crank rg tateis in ghg direction by the larrow in 1g. an y means 0 e wire app ms ff g giigj g 12322 553 Wm be apparent a downward pull through the blocks, on the scale, which ull can be read and may be ob- 1 of the drawmg 1s from elevatlon of the served at a d i stance. As the lever rotates, the

R i hand on the pointer moves from zero position or 2 a 51d? Flevaatlon Thereof; a point near zero to the point indicating the 50 F 3 1S a Partial p VIEW; maximum pull and then gradually returns to ini- 4 is a enlarged elevation of t Slotted tial position. By moving the bolt 28 toward or crank lever; away from the axis of rotation of the crank, the Fig. 5 is an' enlarged plan view of the crank effective length of said crank becomes longer 55 lever bolt; and or shorter and will result in a. greater or less a;

maximum pull. By adjusting the nut 15, the wire can always be kept under tension and the various parts in the chain of elements under tension can be given a preloading and thus increase the maximum tension on the same, including the force or pull tending to separate the two or more blocks.

I claim:

1. Demonstration apparatus comprising a support, a plurality of gauge blocks wrung together, a fastening device attached to each of said blocks, means connecting one of said fastening devices to said support, a tension member connected to the other of said fastening devices, a continuously operating mechanical means for intermittently applying a pull to said tension member insuflicient to separate said blocks, and an indicating instrument connected between said support and said pull applying means to indicate said pull whereby said apparatus demonstrates that the adhesion of said blocks is in excess of the. maximum reading of said instrument.

2. Demonstration apparatus comprising a support, a scale suspended therefrom, a plurality of gauge blocks wrimg together, the upper of which blocks is connected to said scale, a tension member connected to the lower of said blocks, a motor driven speed reduction .device having a crank thereon and means connecting said tension member to said crank to apply an intermittent force to said blocks insuiiic'ient to pull them apart, said scale indicating an adhesion inexcess of the maximum force applied, whereby said blocks are alternately pulled downwardly and restored to initial position.

3. Demonstration apparatus comprising a support, a scale suspended therefrom; a plurality ofgauge blocks wrung together, the upper of which blocks is connected to said scale, a tension mem-" ber connected to the lower of said blocks, a motor driven speed reduction device having a slotted crank thereon, a pin adjustably mounted in said slot and a pulley beneath said blocks under which gether the upper of which has an eye bolt connected to said scale and the lower of which has an eye bolt for attachment of a flexible tension member, a pulley mounted on said base beneath said blocks, a motor driven reduction gearing device mounted on said base at one side of said pulley, said tension member passing downwardly and under said pulley to said reduction gearing device, the latter having a rotating shaft, a slotted crank thereon, a pin adjustable in said slot and a ring surrounding said pin to which said tension member is fastened, whereby the rotation of said arm will pull said blocks downwardly, intermittently, and said scale will restore them to normal position, after each downward pull.

CARL EDVARD JOHANSSON. 

